The Urwerk UR-202 watch uses a pair of tiny spinning air-turbines to wind itself:
The UR-202's twin turbines are coupled with the winding rotor. According to the position of the selector lever, the turbines act as shock absorbers.In normal activity they cushion sharp movements of the rotor. This reduces wear and increases the lifespan of the movement.
While the selector position is continuously variable, the three principal positions are: normal activity, where the turbines spin freely; vigorous activity, where the air pressure generated by the turbines reduces the winding rate by approximately 35%; and extreme activity, where the turbines and rotor are fully blocked.
